As for a beverage bottle designed for keeping a leftover carbonated beverage from going flat, it is conventionally known that there is a PET bottle having a trunk section formed in the shape of a bellows (3), wherein when a carbonated beverage is left over in the bottle, the bellows (3) is shrunken in accordance with the amount of leftover carbonated beverage, and thereafter, the bottle is sealed by a cap (1) in state where the bellows is shrunken, as disclosed in a patent document 1, for instance.
According to the PET bottle of this type, a misunderstanding arises such that it seems as if the PET bottle is capable of keeping the leftover carbonated beverage from going flat. As a matter of fact, the above patent document 1 contains a description to the effect that the PET bottle is capable of keeping the leftover carbonated beverage from going flat.
However, the PET bottle disclosed in the above patent document 1 fails to keep the leftover carbonated beverage from going flat.
This is because an action of merely sealing the bottle by the cap (1) with the bellows (3) shrunken in accordance with the amount of leftover carbonated beverage brings about a phenomenon in which carbon dioxide is released freely from the leftover carbonated beverage, and accordingly, the bottle comes to be returned to the original state (or the state in which the bellows (3) is expanded) by the thus released carbon dioxide.
Alternatively, a carbon dioxide divergence preventing device for a carbonated beverage in a PET bottle is also conventionally known, which has two holding plates (2) connected with each other by a hinge (1), a squeezing belt (3) fixed to one holding plate (2), and a slit-shaped through hole (4) provided in the tip of the other holding plate (2) to permit the squeezing belt (3) to pass through, as disclosed in a patent document 2, for instance.
The carbon dioxide divergence preventing device of this type allows the PET bottle to be maintained in the squeezed state in accordance with the amount of leftover carbonated beverage, and is therefore capable of keeping the leftover carbonated beverage from going flat.
However, it is inconvenient to use the carbon dioxide divergence preventing device in places other than home, because, in order to do so, there is the need for carrying this device.